cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A373272 Triangle read by rows: T(n,k) = sum of all distinct multiplicities in the integer partitions of n with k parts.

Original entry on oeis.org

1, 1, 2, 1, 1, 3, 1, 3, 3, 4, 1, 2, 6, 4, 5, 1, 4, 7, 6, 5, 6, 1, 3, 10, 11, 10, 6, 7, 1, 5, 11, 16, 14, 12, 7, 8, 1, 4, 15, 20, 22, 14, 14, 8, 9, 1, 6, 16, 26, 28, 29, 20, 16, 9, 10, 1, 5, 20, 34, 41, 40, 34, 23, 18, 10, 11, 1, 7, 22, 42, 50, 54, 44, 35, 26, 20, 11, 12, 1, 6, 26, 52, 69, 75, 68, 54, 44, 29, 22, 12, 13
Offset: 1

Views

Author

Olivier Gérard, May 29 2024

Keywords

Examples

			Array begins:
  1;
  1, 2;
  1, 1,  3;
  1, 3,  3,  4;
  1, 2,  6,  4,  5;
  1, 4,  7,  6,  5,  6;
  1, 3, 10, 11, 10,  6,  7;
  1, 5, 11, 16, 14, 12,  7,  8;
  1, 4, 15, 20, 22, 14, 14,  8, 9;
  1, 6, 16, 26, 28, 29, 20, 16, 9, 10;
  ...
T(6,3) = 7 because the partitions of 6 into 3 parts are 4+1+1, 3+2+1, 2+2+2,
  the multiplicities are (1,2), (1,1,1), (3),
  the distinct multiplicities are respectively (1,2), (1), (3),
  contributing 3+1+3 = 7.
		

Crossrefs

Columns k=1-2 give: A057427, A028242.
Main diagonal gives A000027.
Row sums are A373273.
T(2n,n) gives A373104.

Programs

  • Mathematica
    Flatten[Table[
      Plus @@@
       Table[Map[Plus @@ Union[Length /@ Split[#]] &,
         IntegerPartitions[n, {k}]], {k, 1, n}], {n, 1, 20}]]